JIT-28p

JITHistory•Thistext’sidea•Philosophicalchange•TaiichiOhno–Toyota•Just-in-Timemanufacturingistheeliminationofallwasteandcontinuousimprovementofproductivity•Wastemeansanythingotherthantheminimumamountofequipment,parts,space,material,andworkers’timeabsolutelynecessarytoaddvaluetotheproduct.JIT•Thelong-termresultofeliminatingwasteisacost-efficient,quality-oriented,fast-responseorganizationthatisresponsivetocustomerneeds•Addingvaluetoaproductdoesnotmeanaddingcost.•Usersarenotconcernedwiththemanufacturer’scostbutonlywiththepricetheymustpayandthevaluetheyreceive.Manyactivitiesincreasecostwithoutaddingvalueand,asmuchaspossible,theseactivitiesshouldbeeliminated.Waste•Anythingintheproductcyclethatdoesnotaddvaluetotheproductiswaste•Managementisresponsibleforestablishingpoliciesforthemarketsegmentsthecompanywishestoserveandfordecidinghowbroadorspecializedtheproductlineistobe.Standardization•Standardizationreducestheplanningandcontroleffortneeded,thenumberofitemsrequired,andtheinventorythathastobecarried.The“ideal”productisonethatmeetsorexceedscustomerexpectations,makesthebestuseofmaterial,andcanbemanufacturedwithaminimumofwasteWasteinManufacturing•Toyotaidentifiedsevenimportantsourcesofwasteinmanufacturing.Thefirstfourrelatetothedesignofthemanufacturingsystemandthelastthreetotheoperationsandmanagementofthesystem:•1)Theprocess–Consistent,minimumscrap,leastcost•2)Methods-wastedmovement,timeandeffort.ietools•3)Movement–storingcomponents•4)Productdefects–rework,badqualitycustomer•5)Waitingtime–workerand/ormaterial•6)Overproduction–excessinventory•7)Inventory-excessInventoriesroleinJIT•Batchof1000parts•Quality•Rework•SlowsCIP•Batch100•Increasedresponsiveness•Lessinspection•BetterqualityCh15-6©2000byPrentice-HallIncRussell/TaylorOperMgt3/eStandardOperatingRoutineCharacteristicsofJITEnvironment•Flowmanufacturing-onlycertainitems•Cellularmanufacturing–functionallayoutandworkcelllayout•Processflexibility–workerandmachineflexibility.–Quickchangeover–shortensetups•ReducedEOQ,queue,MLT,WIP•ImprovedqualityandprocessflowCh15-8©2000byPrentice-HallIncRussell/TaylorOperMgt3/eManufacturingCellWithWorkerRoutesEnterWorker1Worker2Worker3ExitKey:ProductrouteWorkerrouteMachinesTQM•Qualityisimportantfortworeasons.–Ifqualityisnotpresentinwhatissuppliedtothecustomerandtheproductisdefective,thecustomerwillbedissatisfied.Ifaprocessproducesscrap,itcreatesdisruptedschedulesthatdelaysupplyingthecustomer,increasesthecostoftheproduct.Manufacturingmustensurethattheprocessiscapableofproducingtherequiredqualityconsistentlyandwithasclosetozerodefectsaspossible.Thebenefitsofagoodqualityprogramarelessscrap,lessrework,lessinventory,betteron-timeproduction,timelydeliveries,andmoresatisfiedcustomers.Totalproductivemaintenance•is“preventivemaintenancepluscontinuingeffortstoadapt,modify,andrefineequipmenttoincreaseflexibility,reducematerialhandling,andpromotecontinuousflow.”Uniformplantloading•meansthattheworkdoneateachworkstationshouldtakeaboutthesametime.•Balancingtheline,whichmeansthatthetimetakentoperformtasksateachworkstationonthelineisthesameorverynearlyso.Theresultwillbenobottlenecksandnobuildupofwork-in-processinventory.Pullsystem•Startsattheendofthelineandpullsproductfromtheprecedingoperationasneeded.Theprecedingoperationdoesnotproduceanythingunlessasignalissentfromthefollowingoperationtodoso.Thesystemforsignalingdemanddependsonthephysicallayoutandconditionsintheplant.ThemostwellknownsystemistheKanbansystem.Thedetailsvary,butitisbasicallyatwo-bin,fixed-order-quantity,order-pointsystemValidschedule•Theschedulesetstheflowofmaterialscomingintothefactoryandtheflowofworkthroughmanufacturing.Tomaintainanevenflow,theschedulemustbelevel.Inotherwords,thesameamountshouldbeproducedeachday.Mixed-modelscheduling•Meansthatsomeofeverythingismadeeachdayintheproportionstomeetdemand.Ifdemandshiftsbetweenmodels,theassemblylinecanresponddaily.WeekOnHand123Economy01500Standard6001500300Deluxe8001200Total1400150015001500WeekOnHand123Economy250500500500Standard300600600600Deluxe200400400400Total750150015001500MasterProductionScheduleLeveledMasterProductionScheduleLinearity•isachievingtheplan–nomore,noless•andisusuallyreachedbyschedulingtolessthanfullcapacity.SupplierPartnerships.•Trust•Long-termcommitment•SharedvisionTotalEmployeeInvolvement•AsuccessfulJITenvironmentcanbeachievedonlywiththecooperationandinvolvementofeveryoneintheorganization•Operatorsmusttakeresponsibilityforimprovingprocesses,controllingequipment,correctingdeviations,andbecomingvehiclesforcontinuousimprovement.•Employeesmustbeflexibleinthetaskstheydo.InaJITenvironment,moreemphasisisplacedontheleadershiprole.•Managersandsupervisorsmustbecomecoachesandtrainers,developthecapabilityofemployees,andprovidecoordinationandleadershipforimprovements.EffectsofMPCinJITEnvironment•Forecasting-isshortenedlead-time.•PP–Supplierrelationships,improvedmaterialflow.•MPS–seeslide14–Shorterlead-timesreducetimefences,greatercustomerserviceandclosertomaketoorderenvironment.•MRP–reductiontodailytimebuckets–Noinventory,nonettingands